Moses g



(No Model.)

M. G. FARMER.

ELEGTRO MAGNET.

No. 351,256. Patented Oct. 19, 1886.

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To all whom it may concern:

* UNITED STATES PATENT OFFICE.

MOSES G. FARMER, OF NElV YORK, N. Y.

ELECTRO- MAGN ET.

SPECIFICATION forming part of Letters Patent'No. 351,256, dated Gotober19.1886.

Application filed June 11, 1886. Serial No. 204,886. (No model.)

Be it known that 1, Moses G. FARMER, a citizen of the United States, anda resident of New York, in the county of New York and State of New York,have invented certain new and useful Improvements in Electro-lliagnets,of which the following is a specification, reference being had to theaccompanying drawings.

This invention is animprovement in that class of electro magnets whichare distinguished by a helix and movable core, and which are commonlyknown as axial magnets. 7

The chief object of this invention is to produce a very sensitive magnetof this general character, and at the same time one of great power, bymeans of which a comparatively. t'ecble current may be caused. to exerta strong attractive force. J

The device by means of which. my invention is carried out may begenerally described in the following manner: There are two helices,placed in line in close proximity to each other. Each helix is compound,consisting, really,of twoindependent coils, which I shall designate asthe main and local coils or helices, since they are connected inindependentcircuits, as will be more fully hereinafter explained.\Vithin the local helices are sectional iron cores, tubular, and fixedat short distances apart. The movable portion of the core consists of anumber of iron cylinders carried by a brass rod, the cylinders beingarranged one in each. stationary coresection and formed with a flangethat extends into the space between two adj acentseotions. The localcoils orhelices are included in a local circuit in which there issufticient current to impart polarity to the cores. While the main coilsare in the main or working circuit the local circuit is constantlyclosed, and the other is made and broken, as may be desired. Thedirection of winding of the local coils or helices is such as to. causethe stationary core-sections of each helix to repel the movable coreswithin them and to attract those in the adjacent sections. The maincoils are so wound that a current flowing through them adds its strengthto the current in one local coil and neutralizes that in the other,according to the direction of the current in the main circuit, fromwhich it follows that the armatures may be moved in either direction andtheir movement utilized for various purposes by directing through themain coils a current in the proper direction.

The details of the construction of this device are illustrated in theaccompanying drawings, in which Figure 1 is a vertical central sectionof my improved electro-magnet, showing the circuitconnections; and Fig.2 is a top plan view of the same.

The helices are supported between heads or plates A A, forming part of aframe, in conjunction with theb'ars B B, and are in line with each otherand a short distance apart. Each helix is composed of two coils, as G DO D. The inner helices, G C, are in a branched local circuit, E,containing a battery, F, and a rheostat, G or G, in each branch, bymeans of which the resistances of the two branches may be varied. Theouter helices, D D, are in the main or operating circuit H.

The inner helices, O O, surround stationary tubular cores composed ofthe soft-iron sections K K, which are formed with ashoulder at each endand held apart by the interposed brass or non-magnetic rings a. Theheads A A serve to hold the core firmly together.. Within the tubularsectional cores are the series of armatures L L, carried by a brass rodor tube, M. The armatures L L are short tubes of soft iron formed withflanges b, or in any other manner, so as to contain a greater mass ofiron at that end which is nearest to the end of the next adjacenttubular stationary coresection. The armatures are of a diame ter to fitlooscl y within. the sections K K, and are separated from each other byinterposed rings of non-magnetic metal a. They are secured to the rod ortube M, and the sections K K placed over them in building up the core,so that the heads or flanges Z) will be contained in the spaces betweenthe sections K and permit the rod or tube M to have a longitudinalmovement of limited extent through the helices.

I face the armatures LL with brass or a non-magnetic substance, in orderto prevent adhesion from residual magnetism. in case of cont-act withthe stationary core-sections, and

they are made quite light in comparison with the cores K K. lhe objectisto impart t0 the rod or tube N a limited movement in either direction byclosing the circuit through the coils D D. This movement may be utilizedfor a great many purposes. For example, the instrument may be used inconjunction with proper contacts as a polarized relay, or it may be usedfor opening and closing a valve or ringing a gong, or for any other likepurpose, and it is particularly adapted for operating any suchinstrument where the expenditure of considerable force is necessary, andwhere the current to produce it is comparatively weak. Inorder toaccomplish this the inner coils are wound or the current directedthrough them in such manner as to impart to the ends of the stationarycore-sections in one helix polarities opposite to those in thecorresponding ends of the sections in the other helix. The same currentmagnetizes the inner or movable sections, and by reason of theirrelative positions it imparts to both stationary and movable sectionsthe same polarity at their corresponding or adjacent ends. One end ofeach movable section being larger than the other, and being also nearerto one of the adjacent stationary sections than its smaller end to theother, such larger ends are attracted by the adjacent stationarysections and repelled by those surrounding them. These forces which, byreason of the closed local circuit,are constantly exerted upon themovable armatures are opposite and normally should be equal. To securethis the proper balance is made by adjusting the rheostats G.

The coils D D are so wound that a current flowing through the maincircuit H will circulate around the two cores in the same directiou. Acurrent impulse of given direction, therefore, in the circuit H willassist the local current in one of the helices, G, and neutralize itseffect in the other, so that the movement imparted to the armatures andtheir supporting rod or tube will be toward that helix in which thecurrent is neutralized.

The two coils of the helix may be wound in armatures secured to a rod ortube and mov able within the core-sections, as set forth.

8. The coinbinationot' two co-operating helices, each composed of a mainand local coil, stationary sectional cores contained in said helices,and a series ofarmatures secured to a rod or tube,one armature in eachcoresection, so as to form a compound polarized magnet when energized bya current in the local coils, as set forth.

4. The combination of two co-opcrating helices, each consisting of amain and local coil, stationary sectional cores contained in thehelices, the sections being separated by short spaces and magneticallyinsulated, and a series of cylindrical armatures secured to a rod ortube, and formed with a greatermass of iron at one end, and movablewithi u the core-sections, as set forth.

5. The combination of two cooperating helices, each consisting of a mainand local coil, stationary sectional cores contained in the helices, thesections being separated by short spaces and magnetically insulated,anda series of cylindrical armatures secured to a rod or tube, and formedwith flanges extending into the spaces between the core-sections, as andfor the purpose set forth.

MOSES G. FARMER.

Witnesses:

Tnro'rnY DAME, M. F. KEEFE.

